Compression

The swinstall and swcopy commands can transfer large amounts of data over the network from depots to targets. The SD-UX compress_files option can improve performance by first compressing files that are to be transferred. This can reduce network usage by approximately 50%; the exact amount of compression depends on the type of files. Binary files compress less than 50%; text files generally compress more.

Set this option to true only when network bandwidth is clearly restricting total throughput. If it is not clear that this option will help, compare the throughput of a few swinstall or swcopy tasks (i.e., with and without compression) before changing this option value.

You can use swcopy to compress files and leave them compressed in a target depot or compress before network transfer and uncompress afterward.

Precompressing a depot is advantageous when installing or copying to multiple targets. If the source depot is not already compressed, then each file is recompressed for each target.

You can set uncompress_files to true to leave a depot uncompressed after copying with swcopy. For swinstall, the compress_files option will compress all uncompressed files before network transfer. Files are always uncompressed before installing them to the target file system.

INDEX and INFO Compression

Another way to reduce your network traffic is by compressing INDEX and INFO files from the source depot to the target. You can turn on INDEX or INFO compression by setting the compress_index option to true in the defaults file (/var/adm/sw/defaults).

The SD-UX controller and target agents will request compressed INDEX files from the source agent. If the source agent is read only or an older version of SD-UX, the agent cannot comply; consequently, the client will request a normal INDEX. Otherwise, the source agent will send a precompressed INDEX and INFO or compress it on the fly.

The target agent will then create a permanent compressed INDEX in the target, depot, or root. This saves the next request for a compressed INDEX or INFO from having to compress on the fly.